Eukoenenia glandulosa, Mayoral & Hernández-Borroto, 2023

Mayoral, Jaime & Hernández-Borroto, Samuel, 2023, Palpigrades from Cuba (Arachnida: Palpigradi: Eukoeneniidae), Zootaxa 5296 (3), pp. 475-487 : 476-486

Eukoenenia glandulosa sp. n.

( Figures 1–20 , Table 1 )

Material examined. Holotype, female (UAL-pp-053), Reparto Alamar , Municipio Habana del Este, Provincia La Habana, Cuba. 6–Dec–2021. S. Hernández-Borroto leg. Paratypes, 2 females (UAL-pp-054, UAL-pp-055), same location, and collector as holotype; 28–Nov–2020 (30 m.a.s.l., 23°9’33.225”N - 82°16’39.486”W) .

Description

Body length 788–998 (without flagellum).

Prosoma. Frontal organ with two branches with pointy apical ends ( Fig. 1 ). Lateral organs with a single and pointed blade ( Fig. 2 ). Propeltidium with 10 + 10 setae. Metapeltidum with 3 + 3 setae: t 2 (50–52) longer than t 3 (38–41) and t 1 (25–29) ( Fig. 3 ). Labrum with 5 + 5 setae. Deuto-tritosternum with 3 setae arranged in an inverted and widely open V ( Fig. 4 ). Chelicera with 6 proximal setae in basal segment, p 1 and p 6 thickened and heavily barbed; p 1 the longest, and p 2 the shortest; p 3 with truncated apical end ( Fig. 5 ). Three distal setae: d 3 (59–63) longer than d 2 (34–36) and d 1 (38–41); d 3 long and with small sparse setules, including the apical end; d 2 thinner than d 1 and d 3, with subparallel borders, with tiny setules along the stem of seta and ending in a small crown of 2–3 spines; d 1 thickest of the series, with several apical setules, and only tapering on apical end ( Fig. 6 ). Hand of chelicera with 7 setae, 6 dorsal and 1 ventral: 5 dorsal setae arranged in a straight line approximately in the middle of the segment, plus one external; ventral seta on the anterior portion of the segment. Fingers with 9 serrated teeth ( Fig. 7 ).

Coxal chaetotaxy. Pedipalp coxa with 19 normal setae of different lengths ( Fig. 8 ). Coxa I with 15 setae: 13 normal and two tiny and thin microsetae ( Fig. 9 ). Coxa II with 13 setae: 3 thick, 8 normal and 2 long macrosetae ( Fig. 10 ). Coxa III with 12 setae: 3 thick, 8 normal, and a long macroseta (including a small normal seta proximal to macroseta) ( Fig. 11 ). Coxa IV with 9 setae: 1 thick and 8 normal ( Fig. 12 ).

Legs formula: Pedipalp: tc with 9n; fe 8n; ti 8n; bta 1 with 1n; bta2 5 m, 1n; ta1 with no setae; ta 2 with 3 m, 3n; ta3 with 2 r, fs, cs, m, 14n and a seta with its base greatly expanded or dilated (labeled ds —dilated seta—as in Fig. 17A ) ( Fig. 13 and Fig. 17A ).

Leg I: tc with 13n, fe with 8n, pa with 9n and 1 tb, ti with 9n, bta 1 with 2n, 1 m, 2 tb; bta2 with 1n, 3 m, 2 tb; bta3 with 2 r; bta4 with 4n, 1 m, 1 tb; ta1 with 2r, 1n; ta2 with 3 m, 2n, 1 tb and fs, ta 3 with 2 r, 2 fs, rs, 4 m and 13n (cs not present) ( Figs 14, 15, 16 and 17B )

Leg II: tc with 4n; fe, pa and ti each with 5n; bta with 4 setae (including 2 esd); ta with 9 setae (including one shorter one on distal end).

Leg III: tc with 2n; fe, pa and ti each with 5n; bta with 4 setae (including 2 distal esd); ta with 10 setae (including an r seta (?), not clearly visible).

Leg IV: tc with 3 normal setae; fe with 3 normal setae; pa with 5 normal setae; ti with a thick and 4 normal setae; bta with grt, gla, r, and 2 esp; ta1 with 4 normal setae; ta2 with cs and 6 setae (3 dorsal, 3 ventral) similar in morphology to esp setae.

Basitarsus leg IV (IVbta) relatively short (74) and with 5 setae: grt, gla, r, and 2 esp ( Fig. 18 ). Seta r inserted most proximally (dr/IVbta = 0.15–0.24); gla and grt inserted at the base of the segment and more or less at the same level; esp pair inserted approximately 1/3 from the base of the segment, distal from r, and slightly distal from grt and gla. Length for these setae and ratios are given in Table 1 .

Opisthosoma. Tergites III–VI with 3 + 3 setae: two pairs of t setae (t 1, t 2) between a pair of slender setae (s). Sternite III with 2 + 2 setae. Sternites IV–VI each with two subcylindrically shaped a setae (a 1, a 2), and two pairs of slender setae (s 1, s 2): a 1 29–32, a 2 32–34, s 1 27 and s 2 20 –23 ( Fig. 19 ). A small glandular orifice is present in the middle of sternites IV–VI. 3 + 3 thickened glandular setae with rounded tips are arranged in two submedian triangles on sternites IV and V; these setae are shorter and much thicker (23 long, 5 wide) than a 1, a 2 ( Fig. 19 ). They seem to be associated with a glandular mass located underneath each sternite. Segment VII with 11 setae (5 dorsal and 6 ventral), VIII with 10 setae (4 dorsal and 6 ventral), and segments IX–XI with 8 setae each.

Female genitalia. First lobe with 11 + 11 setae in six transverse rows: 2 + 2, 2 + 2, 1 + 1, 2 + 2 (longer and thicker than the others) and 4 + 4 distal setae (a 1 = 14, a 2 = 14, a 3 = 18, a 4 = 20). Second lobe with 3 + 3 setae, x = 23, y = 20, z = 23 ( Fig. 20 ).

Flagellum. Not preserved

Etymology: The new species is named after the peculiar glandular complex that includes the 3 pairs of glandular setae on sternites IV and V.

Taxonomic remarks

The new species from Cuba shows characters that relates it to only a few species of palpigrades worldwide. In particular, the presence of thickened glandular setae on sternites IV and V is present in only three other species of Eukoenenia : E. paulinae Condé, 1994 from Indonesia, and E. angolensis ( Rémy, 1956) and E. hesperia ( Rémy, 1953) from Angola and Ivory Coast, respectively ( Condé 1994, Rémy 1953, Rémy 1956). E. glandulosa sp. nov. is most closely related to the species from Indonesia: they share the same chaetotaxy on sternites IV–VI, however the morphology of the glandular setae on IV and V is somewhat different. In E. paulinae the glandular setae seem to be a larger version of the a setae, while in the species from Cuba these setae are shorter and thicker. The two species also differ in the number of blades in the lateral organs (1 vs. 3), the number of deuto-tritosternal setae (3 vs. 9), and the length of t 1, t 2, t 3, which are only half as long in the new species (25–29, 50–52, 38–41 vs. 73, 105, 65). The first genital lobe of the Cuban specimens carries an additional pair of setae (11 + 11) compared to the Indonesian species (10 + 10). Overall, the legs of the new species are shorter than those of E. paulinae , as an example, the length from the pedipalp tibia to tarsus III (segments with data for all species) is 219 vs. 455; btaIV length is also shorter 74 vs. 127. It is not possible to compare other relevant characters, such as the number of thick setae on the coxae, as they have not been described for any of the other 3 species.

E. angolensis and E. hesperia can be easily differentiated from E. glandulosa sp. nov. and E. paulinae by the presence of 2 + 2 thick glandular setae on sternite VI (in both species), as well as a different formula of glandular setae on sternites IV and V. E. glandulosa sp. nov. and E. hesperia share the number of lobes in the lateral organs (1) but differ from E. angolensis (2). In addition, the Cuban species carries three deuto-tritosternal setae, while E. angolensis and E. hesperia carry 4–5 and 4, respectively. The two species from Africa apparently lack two a setae (unmodified/non-glandular) on all three IV–VI sternites compared to E. glandulosa sp. nov. and E. paulinae . The female genitalia of E. glandulosa sp. nov. and E. hesperia are similar regarding the number of setae, and both differ from E. angolensis in the presence of the x pair of setae on the second lobe (3 + 3 vs. 2 + 2). According to the pedipalp tibia-tarsus III length, E. hesperia has the shortest legs (158), followed by E. glandulosa sp. nov. (219) and finally, E. angolensis (324); other segments measured follow the same trend, including btaIV (54, 74 and 85, respectively).

Habitat and associated fauna

All three species reported in this work were collected in an area of only 6 m 2. To the best of our knowledge, this is the first time that three palpigrade species have been collected in the same place and in the same micro-tunnels. The new species was collected in micro-tunnels in the mud from a backyard in a suburb of La Habana, Cuba. The substrate was wet and fully saturated with water. The environment was highly anthropogenic, consisting mainly of banana and lemon trees and some recently constructed small human structures ( Fig. 21 ).

E. glandulosa sp. nov. was found sharing this habitat with other invertebrates, mostly macroarthropods and edaphic mesofauna sensu Fragoso et al. (2001) and Cabrera Dávila et al. (2017). Macroarthropods included the earthworm Onychochaeta elegans (Cognetti, 1905) reported previously from Cuba, Panama, Mexico and Colombia ( Rodríguez et al. 2003); several Diplura belonging to the families Japygidae Haliday, 1864 and Campodeidae Meinert, 1865 ; two myriapod species belonging to the Diplopoda and Symphyla: a polyxenid belonging to the Genus Lophoturus Brolemann, 1931 , Family Lophoproctidae Silvestri, 1897 , and a symphylan identified only to family level, Scutigerellidae Bagnall, 1913 ( Domínguez Camacho 2015, Short & Vahtera 2017). The soil mesofauna, which occurred syntopically with the palpigrades, included three species of springtails: Proisotoma tenella (Reuter, 1895) , Folsomia sp. Willem, 1902 and Deuterosminthurus sp. B ̂rner, 1901 ( Díaz Azpiazu et al. 2004); a juvenile specimen of the schizomid Stenochrus portoricensis Chamberlin, 1922 , common in Cuba ( Chamberlin 1922, Teruel 2011) and spread to other parts of the world by human activity; worker ants of Solenopsis geminata (Fabricius, 1804) ; isopods of the genus Trichorhina Budde-Lund, 1908 ( Budde-Lund 1908, Armas & Juarrero De Varona 1994); a pauropod species belonging to the order Tetramerocerata ; and a spider of the Family Oonopidae Simon, 1890 , to which the smallest specimens within the Araneae belong ( Simon 1890, Díaz Azpiazu & Rodríguez Aragonés 1990, Domínguez Rodríguez 2015).

Figures

FIGURES 13. E. glandulosa sp. nov. Paratype. Palp: trochanter–tarsus 2. Scale bar 50μm.

FIGURE 17. E. glandulosa sp. nov. Paratype. A, palp tarsus 3; B, leg I tarsus 3. Scale bar 50μm.

FIGURE 20. E. glandulosa sp. nov. Paratype. Female genitalia. Scale bar 50μm.

FIGURE 21. Habitat of E. glandulosa sp. nov., E. berlesei and E. florenciae, La Havana, Cuba.

FIGURES 1–7. E. glandulosa sp. nov. Paratype. 1, frontal organ; 2, lateral organ; 3, metapeltidial setae (t1–t3); 4, deutotritosternal setae; 5, proximal setae (p1–p6) on basal segment of chelicera; 6, distal setae (d1–d3) on basal segment of chelicera; 7, chelicera, ventral view. Scale bars 20μm.

FIGURES 8–12. E. glandulosa sp. nov. Paratype. 8, coxa of palp; 9, coxa of leg I; 10, coxa of leg II; 11, coxa of leg III; 12, coxa of leg IV. Scale bar 50μm.

FIGURES 14–16. E. glandulosa sp. nov. Paratype. Leg I: 14, trochanter-patella; 15, basitarsus 1+2; 16, basitarsus 3–tarsus 2. Scale bar 50μm.

FIGURE 18–19. E. glandulosa sp. nov. Paratype. 18, Basitarsus leg IV; 19, ventral chaetotaxy, sternites IV–VI. Scale bars 50μm.

Tables

TABLE 1. Measurements (in μm) and ratios for E. berlesei, E. florenciae and E. glandulosa sp. nov. from Cuba. H— holotype, P—paratype.

	E. berlesei	E. florenciae		E. glandulosa sp. nov
	N=2	N=2	H	P1	P2
L	1076–1103	1208–1400	910	788	998
B	281–286	270–275	247	221	220
Pcx	104–108	108	101	97	95
Ptc	124–131	131–135	101	95	97
Pfe	81–91	99–101	81	86	81
Pti	108	119–126	76	70	74
Pbta1	34–41	41	23	23	23
Pbta2	54–59	63	29	25	29
Pta1	27–29	25–27	18	18	16

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